Method of transporting asphalts and the like



Patented June 7, 1938 UNITED STATES PATENT OFFICE METHOD OF TRAN SPORTING ASPHALTS AND THE LIKE William Henry Hampton, Berkeley, Calif., as-

signor to Standard Oil Company of California, San Francisco, Calif., a corporation of Delaware No Drawing.

4 Claims.

This invention pertains to a new and advantageous method of commercially distributing asphalts and the like and relates more particularly to an improved method of transporting the higher melting asphalts in bulk form.

As is well known, a very large proportion of all the asphalt marketed at the present time in regions distant from the point of manufacture is packaged in either metal or wooden barrels orv i always high as compared to bulk handling, while the space wastage in transport is also substantially at a maximum with barrel shaped packages.

Many and varied have been the attempts to find a method whereby the ever increasing volume of asphalt'consumed could be distributed in bulk form, but each such proposal has encountered difliculties so considerable as to preclude adoption on more than a very limited scale under certain very specialized conditions inspite of the enormous potential savings possible to a really operable procedure.

The veryvhard natural asphalts and asphaltites have been shiped in coarsely broken or lump form similar to coal. This procedure has, however, been found impracticable when applied to the lower melting asphalts derived from petroleum.

'The broad idea of dissolving asphalt in an appropriate solvent to give a fluid pumpable at ordinary temperatures has not proven feasible because of the cost of the solvent and/or the difliculties and expense of its removal with a satisfactory re-procluction of the originalasphalt.

The practice of pumping even the lower melting asphalts in molten condition into and out of the bulk shipping container has. due to the very great difliculty of returning the asphalt to a molten condition at its destination, proven applicable to only a very limited extent when the bulk container to be used was a tank car or truck and never at all with larger containers such as tank ships.

I have now discovered that, asphalts and particularly the higher melting asphalts may be produced in or converted to a form in which they may be transferred from vessel to vessel byordi- Application March 28, 1934, Serial No. 717,795

nary bulk fluid handling devices at ordinary tem peratures.

My herein disclosed invention utilizes and extends this discovery to a general system of procedure whereby it now becomes possible in efiect to transport any asphalt in bulk containers, any

' desired distance, with a facility and at an expense substantially identical with that involved in the transportation of an equal volume of an inherently fluid liquid such as water.

The broad object'of this invention is to make available to the producer and to the consumer of asphalts the inherent economies of bulk transportation.

Another object of the invention is to provide a method whereby high melting asphalts and other solid hydrocarbons may by handled at ordinary temperatures by fluid handling devices.

Still another object of the invention is to provide a procedure by which regions remote from a source of supply of asphalts may. be provided with a limited number of, usually two, bulk materials from which asphalts of a wide range of characteristics can be easily prepared to meet the exact requirements of the job in hand.

Further objects of the invention will be readily apparent from the description and discussion which follows.

In the general practice 01 producing asphalts from petroleum, the tar remaining after the more volatile constituents of the crude oil have been removed by distillation at atmospheric pressure is run to steam stills often operated under reduced pressure, whereupon distillation is continued until the bottoms remaining in the still possess the required physical properties, penetration, melting point, etc. The lower the penetration and the higher the melting point desired, the greater is the amount of distillate which it is necessary to take ofl. The residuum is then run from the still, while still hot, into containers for marketing, which, for local distribution, may consist 01' either heated and/or insulated tank cars or trucks, while for distant consumption, wooden or steel barrels are almost invariably used.

In the production of a very hard A grade asphalt having a melting point well above 200 F., which approaches the practical limit to which such distillation may be carried without cracking the residuum, asphalts of all lower melting points progressively exist in the still, commencing with the E" grades of 80 F. or lower melting point and passing in order to "D", "C, B and finally 75% of distillate and 25% to A! grades, as more and more of the distillable components are removed.

It is a fact, long recognized but little used, that if the distillate produced is going from any lower melting' asphalt g onehigher, in the scale is collectedsepara'tely-i' it -may "at" any subsequent time be recombined with such higher member by simply heating the two together, in roughly the proportions in which they originally occurred, with the result that the lower melting asphalt may thus be re-produced with substantially its original properties. Y

I have now discovered that if a high melting asphalt such as the B or preferably the A grade is properly subdivided and properly sluiced, it may be pumped or blown and generally handled and transferred in bulk form by the usual types of fluid transferring equipment and may thus be transported in any desired type of bulk liquid containers.

For instance, if an A grade asphalt is run hot from the still through a properly constructed orifice plate into relatively cold water, it assumes the form of shot" particles which, while tending more or less toward a tear-drop form, retains the essential characteristics of spheres to the point that their suspensions in ordinary fluids such as water or air are readily handled by fluid means.

I have thus found that when asphaltic shot or tear-drops averaging from 2 to 5 millimeters in diameter are produced and admixed with sufficient water, usually more than 30% of their gross volume, a slurry results which may be pumped by a centrifugal pump or transferred by other suction or blowing systems with a facility substantially equal to that possible in handling water alone.

Such a slurry may be pumped into and out of the hold of a tank ship and since the shot in such condition shows little or no tendency to coalesce or stick together, particularly so long as the voids between particles remain substantially filledwith water, a high melting asphalt in this form may be stored for any desired time or shipped any desired distance with all of the advantages and economies inherent in bulk storage and shipment.

Since the higher melting A and B grades of asphalt are utilized in much smaller quantities than the softer C, D and E grades which comprise the bulk of the road building and general construction asphalts, the foregoing discov ery will flnd its'widest application in making possible the economical distribution of these softer products. The shipment-of a low melting asphalt. by my method is, of course, indirect since it is not the low melting asphalt as such that is shipped, but "rather the componentsfrom which it may be re-produced upon arrival at the point of ultimate consumption.

My invention may be well understood by reference to the following specific example.

In the distillation of a typical California crude, if, when the contents of the still approximates a 300 penetration or E grade asphalt, the distillate passing over isv segregated and collected until an A grade,approximately 220240 F. melting point, residuum remains in the still, roughly of asphalt, A grade,

will result. The A grade asphalt, --having a specific gravity slightly greater than unity, may then beconverted to shot by proper injection intowater, as previously described, and will thus be inform for bulk shipment. The distillate, a viscous liquid of viscosity about 1600 sec. Saybolt universal at F., may be shipped in bulk by the usual methods. Upon arrival at the point of consumption, this distillate is charged to the asphalt heating equipment which would ordinarily be employed in melting the finished asphalt shipped in conventional package form prior to use. It is heated to 350-400'F. and the A" grade shot,'from which the water has been drained and/or blown as completely as possible, are slowly added. Upon striking the hot oil, the slight amount of water still adhering to the shot is flash vaporized and the hard asphaltwill passv readily into solution and an E grade asphalt of more or less the same properties as that existing in the still at the time segregation of the distillate I was started, will result.

In addition to the economies and convenience accruing from the bulk shipment of two such asphalt components, over the ordinary package shipment of finished asphalts, another' advantage of almost equal magnitude results'from" my method of procedure in that the two components may be recombined in any desired propor-' tions. Thus, an asphalt of any desired proper-.

ties intermediate between the E grade existing in the still at the start of segregating the distillate and the A? grade actually shipped may be reproduced at the will and option of the consumer.

The extreme simplicity and convenience of a method whereby a whole range ofasphaltic products of a given type may be distributed through the economical bulk shipment of but two materials and its supreme flexibility so far as the consumer is concerned will readily be understood and appreciated by those skilled in the art.

In general any asphalt, natural 'or prepared,

steam refined or air blown, or in fact any similar hydrocarbon which is solid at normal temperatures may be transported in bulk entirely free from all the disadvantages of package distribution by 'a proper application of the foregoing procedure. Asphalts or other products of less than about F. melting point being handled by the two component method, while asphalts of greater than about 170 F. melting point may be shipped directly in shot or other appropriate subdivided form.

While the shot form herein described will usually be found to be the easiest and most economical form of subdivision to produce as well asbeing most free flowing and having the least other fluids such as air may, under certain conditions, be'substituted. While it might occasionally be desirable to ship less water than necessary to fill the voids and with the higher melting products it might be found entirely practicable so to. do it will, in general; be found to be good insurance against the highly undesirable results that would attend coalescence or aglomeration to keep the voids full of water or other similar liquid at all times.

In such application of this invention as contemplates the use of my two component method,

the point at which collection of the distillate should be begun will, in general, depend upon the softest grade of asphalt which it is desired to provide to a given region or locality.

Certain other modifications of the procedure herein described will be apparent to those skilled in the art and will be readily recognized as a part of my invention in its broadest scope.

Having now described my invention and the methods whereby it may be utilized to advantage, what I claim is:

1. The method of transporting to' a region remote from the point of its production, an asphalt of melting point greater than about 170 E which comprises the steps of pumping said asphalt in the form of free-flowing, shot-like particles of substantially uniform size and several millimeters in average diameter admixed with water into the hold of a tank ship, of maintaining said particles in said hold continually wet with water at substantially atmospheric temperature during transport and of finally pumping said asphalt particles, admixed with water, from said ships hold at substantially atmospheric temperature.

2. The method of transporting asphalt as in claim 1, wherein the voids between asphalt particles are maintained full of water during trans- 170 F. to free flowing shot-like particles oi 2' to 5 millimeters average diameter, of transferring said particles by fluid handling means to a bull: container, of maintaining said particles in said container wet with an aqueous medium during transport and of subsequently removing said asphalt from said container by fluid handling means at substantially atmospheric temperature.

4. K method for the bulk transportation of asphalt as in claim 3 wherein the voids between particles are maintained substantially filled with the aqueous medium.

WILLIAM HENRY HAMPTON. 

